In certain situations, it may be necessary to enter an area that is held by terrorists or other adversaries to overcome them and, if necessary, to free any hostages they may be holding. The area could be a house, room, the inside of an airplane, etc. It could also involve secured areas, bank robberies, violent demonstrators, etc. These operations can be extremely dangerous, as the terrorists can be expected to open fire as soon as they see someone entering the area that they control.
U.S. Pat. No. 7,220,957 describes a prior art approach for disabling adversaries using pulses of light. The '957 patent uses a control unit that transmits trigger pulses to both a lighting subsystem and a viewer subsystem. The lighting subsystem generates a flash of light every time it receives a trigger pulse from the control unit, and the viewer subsystem closes its shutter every time it receives a trigger pulse from the control unit. But this approach has a number of drawbacks. For example, if the adversary obtains one of the viewer subsystems, the adversary can use it to protect themselves from the light pulses. Second, if the transmission of the trigger pulse from the control unit to the viewer subsystems is disturbed (e.g. due to interference or jamming) or fails to reach the viewer subsystem, the shutters will not close at the proper time, and the law enforcement personnel using the system could also be disabled by the flashes.